sadly, hitting m or nearly any other key had zero effect. the only key, f12, did take a screenshot. i can get past the main menu and see some sort of character selection type screen, very briefly. i tried hitting m and stuff there too.

There was a video card update that hit yesterday that doesn't allow me to alt-tab out of the game anymore. If I do, I get exactly what you're describing. I can alt-tab back into the game though. You might try that. Its possible something hiccuped during loading and it tried to minimize on you.